A humidity control apparatus including liquid absorbent such as an aqueous lithium chloride solution, and moisture permeable membranes through which only water vapor passes and through which the liquid absorbent does not pass has been conventionally known. For example, PATENT DOCUMENT 1 describes a humidity control apparatus that is capable of selecting one of a dehumidification mode or a humidification mode (Paragraphs [0031]-[0033] and FIG. 8 of PATENT DOCUMENT 1). The humidity control apparatus includes an absorbent circuit through which liquid absorbent circulates, and a refrigerant circuit through which refrigerant circulates to perform a refrigeration cycle.
The absorbent circuit includes a moisture absorber and a moisture desorber. The moisture absorber includes an air passage through which air to be supplied into a room flows, and a liquid passage through which liquid absorbent flows. The air passage and the liquid passage are separated by a moisture permeable membrane. In contrast, the moisture desorber includes an air passage through which air to be discharged to outside the room flows, and a liquid passage through which liquid absorbent flows. The air passage and the liquid passage are separated by a moisture permeable membrane.
The absorbent circuit includes a passage extending from the moisture absorber to the moisture desorber and connected to a heater, and a passage extending from the moisture desorber to the moisture absorber and including a cooler.
When the humidity control apparatus is operated in a dehumidification mode, liquid absorbent cooled by the cooler flows into the moisture absorber. In the moisture absorber, moisture in target air is absorbed by the liquid absorbent to dehumidify the target air. In this case, the concentration of the liquid absorbent is reduced by the amount of moisture absorbed. The dehumidified target air is supplied into the room.
In contrast, the liquid absorbent that has absorbed the moisture in the moisture absorber is heated by the heater, and then flows into the moisture desorber. In the moisture desorber, the moisture in the liquid absorbent is released into regeneration air to humidify the regeneration air. In this case, the concentration of the liquid absorbent is increased by the amount of the moisture released, and the liquid absorbent is therefore regenerated. The humidified regeneration air is discharged to outside the room.
The liquid absorbent from which the moisture has been released in the moisture desorber is again cooled by the cooler, and then flows into the moisture absorber. As such, the humidity control apparatus dehumidifies the room such that while the liquid absorbent repeatedly absorbs and desorbs moisture, the liquid absorbent circulates through the absorbent circuit.